National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

A Few Clouds

70°F

21°C

Humidity 76%
Wind Speed SW 9 mph
Barometer 29.98 in (1015.2 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Last update 24 Jun 8:56 pm EDT
Extended Forecast for

Stony Brook NY

  • Tonight

    Tonight: Mostly clear, with a low around 64. West wind around 5 mph becoming calm in the evening.

    Low: 64 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 80. Calm wind becoming south 5 to 8 mph in the afternoon.

    High: 80 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: A slight chance of showers before 2am, then a chance of showers and thunderstorms between 2am and 5am, then showers likely and possibly a thunderstorm after 5am. Mostly cloudy, with a low around 66. South wind 8 to 11 mph. Chance of precipitation is 60%.

    Low: 66 °F

    Slight Chance
    Showers then
    Showers
    Likely

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 8am, then a slight chance of showers between 8am and 2pm. Partly sunny, with a high near 82. Southwest wind around 7 mph. Chance of precipitation is 60%.

    High: 82 °F

    Showers
    Likely then
    Slight Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms, then showers likely after 11pm. Mostly cloudy, with a low around 68. Southwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 68 °F

    Chance
    Showers then
    Showers
    Likely

  • Saturday

    Saturday: Showers likely, mainly before 2pm. Mostly cloudy, with a high near 77. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 77 °F

    Showers
    Likely

  • Saturday Night

    Saturday Night: A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 65.

    Low: 65 °F

    Chance
    Showers then
    Mostly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 81.

    High: 81 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 66.

    Low: 66 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 64. West wind around 5 mph becoming calm in the evening.
Thursday
Mostly sunny, with a high near 80. Calm wind becoming south 5 to 8 mph in the afternoon.
Thursday Night
A slight chance of showers before 2am, then a chance of showers and thunderstorms between 2am and 5am, then showers likely and possibly a thunderstorm after 5am. Mostly cloudy, with a low around 66. South wind 8 to 11 mph. Chance of precipitation is 60%.
Friday
Showers likely and possibly a thunderstorm before 8am, then a slight chance of showers between 8am and 2pm. Partly sunny, with a high near 82. Southwest wind around 7 mph. Chance of precipitation is 60%.
Friday Night
A chance of showers and thunderstorms, then showers likely after 11pm. Mostly cloudy, with a low around 68. Southwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Saturday
Showers likely, mainly before 2pm. Mostly cloudy, with a high near 77. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday Night
A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 65.
Sunday
Mostly sunny, with a high near 81.
Sunday Night
Mostly clear, with a low around 66.
Monday
Sunny, with a high near 83.
Monday Night
Partly cloudy, with a low around 68.
Tuesday
Mostly sunny, with a high near 86.
Tuesday Night
A 30 percent chance of showers. Partly cloudy, with a low around 68.
Wednesday
Mostly sunny, with a high near 84.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.15°W (Elev. 36 ft)
Last Update:
2:41 pm EDT Jun 24, 2026
Forecast Valid:
10pm EDT Jun 24, 2026-6pm EDT Jul 1, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation